The present invention relates generally to a suction accumulator for a refrigeration system and, in particular, to a suction accumulator that also functions as a receiver and a heat exchanger.
It is known in the art to which this invention pertains to provide a suction accumulator between the evaporator and compressor of a refrigeration system in order to protect the compressor from possible damage. Vaporized refrigerant is received from the evaporator and passed on through the suction accumulator to the compressor. Any raw liquid is metered back to the compressor at a rate that will not result in damage to the compressor.
In recent years, primarily for reasons of energy savings and improved efficiency, it has often become the practice to flood the evaporator, or "low side" of the refrigeration suction accumulator, wherein evaporation takes place, reducing the surface temperature of the accumulator below ambient dew point, which causes sweating of the accumulator surfaces. Sweating of the accumulator ultimately leads to rusting, and possible accumulation of water on surfaces beneath the accumulator.
One expedient that has been employed in an effort to eliminate the sweating and ultimate rusting problems has been to wrap or encase the suction accumulator with one or more layers of insulation. However, this is costly from a material and labor standpoint. Also, difficulty has been encountered in providing an airtight insulative seal, ultimately resulting in the described sweating and rusting problems.
It has further been proposed to position a suction accumulator within a receiver, and to admit into the space therebetween high temperature liquid refrigerant from the condenser. A structural arrangement of this character is shown in the U.S. Pat. No. 3,212,289. As is described herein, the relatively warm refrigerant prevents moisture in the atmosphere from condensing on the accumulator which contains relatively cold refrigerant. The patented arrangement also provides an efficient heat exchange between the relatively cold low pressure refrigerant in the accumulator and the relatively warm high pressure refrigerant in the receiver.
The provision of a dead air space between a suction accumulator and a surrounding sealed vessel or container is effective to a large degree in precluding sweating and subsequent rust formation upon the accumulator walls. The insulative property of the space provided by the novel structure of this invention may be further enhanced by evacuating the space. The structure resulting may be considered similar to that of a vacuum Thermos bottle. Additionally, enhancement of the novel purposes of this invention may be accomplished by provision of means effective to prevent sweating of the inlet and outlet connections to and from the suction accumulator. These concepts are shown in the U.S. Pat. No. 5,479,790.